The present invention relates generally to exercising devices and more particularly to devices for exercising leg muscles.
The standard manner used to exercise leg muscles is to lift heavy barbells held on the shoulders during deep "squat" movements. The movement upward from the deep squat position is very slow. This exercise builds leg muscles, but does not promote quickness. It also results in considerable strain being placed on the back and spine. Many injuries have been reported as a result of such exercise programs. It is relatively inefficient since the weight against which the user must work is situated on the shoulders at a substantial distance from the area of the body (the legs) being exercised.
An alternative to the "squat" apparatus described above is the relatively recent use of "sitdown" leg exercisers in which the user sits on a stationary seat and places his or her feet on horizontally spaced pedals. The user pushes to shift the pedals horizontally until his or her legs become straight. The pedals are then allowed to return to the original position by bending the knees and allowing the feet to move back toward the torso. The user pushes against the pedals with his or her back braced against a backrest of the seat. Back strain is therefore avoided.
A difficulty remains in exercising the leg muscles to promote both strength and quickness. To do this, there must be some form of quick "springing" action available to the legs. This can be done by jumping or, theoretically, by pushing the pedals with such force that they leave engagement with the feet when the legs become straight and locked. This is very impractical and extremely hazardous due to the returning force of the pedals. If the feet are not correctly positioned, the pedals will return and strike against the upper part of the user's legs. This can result in severe injury.
U.S. Pat. No. 2,783,045 granted to L. R. Bosch, in 1957 discloses a push-pull exerciser in which the user rests against an inclined table to perform deep "squat" exercises. Some improvement in safety is made by keeping the back straight and resting against a flat guide surface. However, the weight must still rest on the shoulders of the user. The problem of developing quickness along with leg strength remains unsolved.
A toy seesaw set is disclosed in U.S. Pat. No. 3,420,522 to Elliot, granted in 1969. Elliot shows playground equipment with a single seat at the end of a cantilevered arm. The other arm end is supported at a pivot and a spring which yieldably resists movement of the seat in a downward "seesaw" arc. The Elliot device is intended to reduce forces required to be applied through the rider's legs and is designed more for amusement than for exercise.
The present device eliminates the dangers associated with prior "squat" type exercising, and the failure of sitting type apparatus to develop quickness of thrust in athlete's legs. The present device makes use of a suspended frame-mounted seat that will pivot freely about an elevated horizontal axis. Weights can be added to or removed from the frame, thereby selectively adjusting resistance to pivotal motion about the axis. The user can sit on the seat and push rearwardly against a wall or other stationary surface, causing the frame to pivot freely outward in the opposite direction. The user's legs can relax as the frame pivots outwardly from the wall, then flex again as the frame returns toward the wall. Quickness of leg thrust and leg strength are both developed through use of the present apparatus without accompanying danger of back strain or spinal damage.